Access to indenofurans and indenopyridines via annulation of heterocyclic ketene aminals, o-phthalaldehyde and cyclic 1,3-diketones

Abstract

An efficient and concise method was developed for access to indenofurans and indenopyridines through a one pot, three-component protocol from heterocyclic ketene aminals, o-phthalaldehyde and 1,3-diketones under catalyst-free conditions. The indenofurans and indenopyridines were formed via aldol condensation, a regioselective aza–ene reaction, imine–enamine tautomerization and intramolecular cyclization.